1. Field
The present invention relates to a hard coating composition. More particularly, the present invention relates to a hard coating composition that provides superior antibacterial properties, anti-fouling functions and anti-static properties, and other improved physical properties such as surface resistivity, transparency, hardness and scratch resistance.
2. Description of the Related Technology
In general, functional hard coating materials have been widely used to protect a variety of products in the fields of construction parts and exterior decorative parts for automobiles, paper, lumber, furniture, soundproofing walls, optical materials, cosmetic containers and display devices. With recent advances in display devices, including LCDs, PDPs and projection TVs, there has been an increased demand for a functional hard coating material for protecting the surface of these display devices. In addition, a hard coating material has been widely used for household appliances and portable electronic devices for preventing scratches on their surfaces. A hard coating material may also be used for walls of a clean room for semiconductor processing.
Japanese Patent Application Publication No. Hei 5-214044 discloses a hard coating composition. The composition comprises a poly-functional monomer containing three or more (meth)acryloyl groups, and a mono- or bi-functional acrylic monomer. The acrylic monomer is selected from the group consisting of polyethylene glycol methacrylate, polyoxyethylene glycol acrylate, polyethylene glycol methacrylate and polypropylene glycol methacrylate.
Japanese Patent Application Publication No. Hei 5-214045 discloses another coating solution composition. The composition comprises a polyfunctional monomer containing three or more (meth)acryloyl groups, and an acrylic monomer selected from the group consisting of polyethylene glycol methacrylate, polyethylene glycol dimethacrylate, polyethylene trimethacrylate and polyoxyethylene glycol tetramethacrylate.
Further, Japanese Patent Application Publication No. Hei 5-186534 discloses a UV-curable hard coating composition. The composition comprises a phosphoric ester having acryloyl or (meth)acryloyl group, an organic compound having at least one UV-curable functional group and at least one tertiary amine group in the molecule, and an organic compound having at least two active ethylene groups in the molecule.
Since most of the above hard coating compositions have been developed mainly for improving the scratch resistance of hard coatings, they do not have anti-static functions. In some hard coating compositions having anti-static functions, a component for the anti-static functions is an ionically-conductive material simply added to the hard coating compositions without binding to a matrix. Thus, the anti-static functions of the hard coating compositions do not last a long period of time.
In addition, since the hard coating has a low surface hardness of about 3H to 4H (pencil hardness), numerous attempts have been made to increase the surface hardness of the hard coating. For example, Japanese Patent Application Publication No. 57-074369 discloses a coating composition comprising a polyfunctional acrylate monomer as a photocurable resin, an inorganic filler powder and a polymerization initiator. Further, Japanese Patent Application Publication No. 58-500251 discloses a photopolymerizable composition comprising an inorganic filler material consisting of surface-treated silica or alumina. However, these compositions fail to satisfy the recent requirement for a high surface hardness of hard coatings.
The above-described hard coating compositions and transparent hard coating sheets using the hard coating compositions do not sufficiently satisfy the requirements for high functionality and various physical properties according to recent advances in display devices and other devices, e.g., cell phones. Thus, there is a need to provide a hard coating composition that has superior anti-fouling functions and anti-static properties, exhibits various improved physical properties, including surface resistivity, transparency and scratch resistance, and produces no pollutants.
The discussion in this section is to provide information about related technology and does not constitute an admission of prior art.